Synthesis of Silylated Cyclobutanone and Cyclobutene Derivatives Involving 1,4-Addition of Zinc-Based Silicon Nucleophiles

A copper-catalyzed conjugate silylation of various cyclobutenone derivatives with Me(2) PhSiZnCl ⋅ 2LiCl or (Me(2) PhSi)(2) Zn ⋅ xLiCl (x≤4) to generate β-silylated cyclobutanones is reported. Trapping the intermediate enolate with ClP(O)(OPh)(2) affords silylated enol phosphates that can be further engaged in Kumada cross-coupling reactions to yield silylated cyclobutene derivatives.